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W. H. ARMSTRONG'.. PROPE,LLER.- APPLICATION HLED SEPT. 2a, 1011.:

$51 N. 8. MM"

Patented June 17, \l 919.

2'SHEETS-SHEET 1.

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W. H. ARMSTRONG.

PPPP EL LER 7 Patented June 17, I919. 2'JSHEETS EEEEE 2.

WILLIAM H. ARMSTRONG, OF WASHINGTON, DISTRICT OF COLUMBIA.

PROPELLER.

Specification of Letters Patent.

Patented June 1'7, 11919..

Application filed September 26, 1917. Serial No. 193,303.

To all whom it may concern Be it known that 1, WILLIAM H. Airmsrnomaacitizen of the United States, res1ding at Washington, in-the District ofC0- lumbia, have invented a new and useful Propeller; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as willenable others skilled in the art to which itappertains to make and use the same.

The present invention relates to certain new and useful improvements inscrew propellers, and has for its object'to provide a device of thischaracter Which embodies novel features of construction whereby it canbe used with the maximum efficiency upon boats, aeroplanes, fans, andthe like, the design being such that the blades will take a firm holdupon the particular fluid medium in connection with which it is used andenable a maximum speed and power to be obtained from the energy expendedin driving the same.

Among the provide a propeller for the propulsion of marine vessels, theblades of the propeller having a large surface for engagement with thewater, and being adapted to have sucha pitch as to give a strongbackward pull when the propeller is reversed, tllereby enabling thevessel to be manipulated in a most effective manner for dodging atorpedo in theevent it may be attacked by a submarine. This strongbackward pull which can be obtained by the use of the propeller wouldenable the forward progress of the vessel to be quickly checked whenevernecessary. v

A further object "of the invention is to provide a propeller which canbe driven at the high speed required upon aeroplanes without danger ofbreaking and jeopardizing the lives of the aviators. The risks anddangers of aerial navigation will thus be greatly decreased by the useof a propeller of this character; and at the same time the driving powerof the engine'will be utilized to the greatest advantage.

Still further objects of the invention are to provide a screw propellerwhich is comparatively simple and nexpensive in its construction, whichcan be readily assembled and taken apart, and which embodies a noveldesign whereby a maximum efiiciency and power is obtained.-

With these and other obiects in view, the

anetal blanks objects of the invention is to source, of power.

invention consists in certain novel combinations and arrangements of theparts as will more fully appear as the description proceeds, the novelfeatures thereof being pointed out in the appended claims.

For a full understanding of the invention,

reference is to be had to the following description and accompanyingdrawings, 1n

which Figure 1 is afront elevation of a screw propeller constructed inaccordance with the invention.

' Fig. 2 is a side elevation of the same.

Fig. 3 is an enlarged side elevation of the hub member to which thepropeller blades are'attached, portions being broken away and shown insection to illustrate more clearly the details of construction.

Fig. 4 is a plan view of one of the sheet from which -the propellerblades are formed.

Fig. 5 is a perspectiveview of the blank after it has been bent intoshape.

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the drawings by the samereference characters.

' Referring to the drawings, which illustrate one possible embodiment ofthe invention, the numeral 1 designates a propeller shaft which may bedriven from any suitable The propeller hub is fitted upon the end of theshaft 1, said hub including a spacing sleeve 2 and a pair of opposed endcaps or heads 3 and 3 respectively, which fit against the ends of thesleeve 2 and are held in a properly spaced relation thereby. The cap 3at the end of the shaft preferably has a rounded end, as indicated onthe drawing. The two end caps 3 and 3 are formed with corresponding setsof short radial arms 4, the ends of the arms being bent inwardly at 4?so as to eX- tend parallel to the axis of the shaft 1, said armsterminating in outwardly projecting bifurcated clip members 5 whichreceive the ends of the propeller blades 6. These bifurcated clips 5 areinclined and arranged at an angle to the axis of the propeller shaft 1,and the sides thereof are provided with ing sleeve 2 and shaft 1,thereby locking the hub member rigidly in position upon the shaft andholding'the end caps 3 and 3*, as well as the sleeve 2, in properrelation to each other.

Each of the propeller blades'6 is formed of a single piece of sheetmetal which has an eccentrically arranged opening 6 therein, the narrowside of the plate being severed by a radial slit 6", as indicated byFig. 4. The free ends provided by this slit 6" are sprung laterally inopposite directions from the plane of the sheet metal blank, therebytwisting the blade into proper shape and imparting a pitch thereto sothat it will act as a screw element for propelling a marine vessel,airship, or the like. A series cftthesej propeller blades 6 are arrangedaround the propeller shaft 1 and connected to the clips 5 of the hub,and such a propeller has been found to possess great efficiency and tohave a maximum propulsive power for the energy expended in driving thesame. When the propeller is to be used upon a marine vessel which mustrisk the possibility of an attack by a hostile submarine, the pitch ofthe blades is such that a maximum backward pull or reversing power ispossible, this being obtained even.

with the possible loss of some of the direct power of the propeller,since this backward pull or reversing power is essential to anefi'ective manipulation of the vessel when an attempt is made to destroyit with a torpedo fired from a submarine.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent, is

1. A screw propeller including a hub member adapted to be fitted upon ashaft and formed with aspacing sleeve and end caps which are providedwith corresponding sets of laterally projecting bifurcated clips,transverse pins extending through the spacing sleeve and engaging theend caps to hold the members in position, and looped propeller bladesformed of flat plates and having the extremities thereof secured withinthe bifurcated clips of the end caps.

2. A screw propeller including a hub mem-v 'to the axis of the sleeve,

ber adapted to be fitted upon a shaft and formed with a spacing sleeveand end caps which are provided with corresponding sets oflaterallyprojecting arms, the ends of the arms being bent inwardly parallel tothe sleeve and terminating in outwardly projecting clip members,transverse pins extending through the inwardly ibent ends of thelaterally projecting arms and also through the spacing sleeve to holdthe members in proper relation, and looped propeller blades formed offlat plates and having the extremities thereof secured within thebifurcated clips of the end caps.

3. A screw propeller including a hub member adapted to be fitted uponashaft and formed with a spacing sleeve and end caps which are providedwith corresponding sets of laterally projecting arms, the ends of thearms being bent inwardly parallel to the sleeve and terminating inoutwardly proj ecting bifurcated clips arranged at an angle and loopedpropeller blades formed of flat plates and gradually decreasing in widthfrom the middle portions to the extremities thereof, said extremitiesbeing secured within the bifurcated clips of the end caps.

A screw propeller including a hub mem- :ber adapted to be fitted upon ashaft and formed with a spacing sleeve and end caps which are providedwith corresponding sets of laterally projecting arms, the ends of thearms being bent inwardly parallel to the sleeve and terminating inoutwardly projecting bifurcated clips arrangedat an angle to the axis'ofthe sleeve, and propeller blades formed of substantially circular platesof sheet material having eccentric openings therein and slit radially atthenar-' row sidethereof, the free ends provided by the slit being drawnapart and engaged by

